Alkylation of aromatics with a ferrous chloride catalyst



Patented June 2 5, 1946 AROMATICS WITH A FER- ALKYLATION on 2,402,847 I OFFICE ROUS CHLORIDE CATALYST Louis Schmerling and Vladimir N. Ipatiefl, Chicago, Ill., assignors-to Universal Oil Products Company, Chicago, 111., a corporation of Delaware No Drawing. Application March 31, 1941,

Serial No. 386,109

1 This invention relates to the treatment of arcmatic hydrocarbons to produce allwlated aromatic hydrocarbons. More specifically the process is concerned with the production of mono-alkylated 12 Claims. (Cl. 260-671) terial comprising essentially a granular composite of ferrous chloride and a carrier.

In one specific embodiment the present invention comprises a process for producing alkylated aromatic hydrocarbons which comprises subjecting an aromatic hydrocarbon and an alk'ylating agent selected from the group consisting of oleflns and olefin-producing substance to contact under alkylating conditions in the presence of a catalyst containing ferrous chloride as its active ingredient.

Aromatic hydrocarbons, such as benzene, toluene, other alkylated benzenes, naphthalene. alkylated naphthalenes, other poly-nuclear aromati'cs, etc., which are alkylated by olefinic hydrocarbons as hereinafter set forth, may be obtained by the distillation of coal, by the dehydrogenation and cyclization of aliphatic hydrocarbons and of alkylated aromatic hydrocarbons, and by other means.-

Olefins utilizable as alkylating agents may be as these generally lose hydrogen halide in the presence of the above indicated catalysts and the resulting olefinic hydrocarbons serve as alkylating agents. In the appended claims, the term "olefin is to be understood as including oleflns formed in situ from olefin-producing substances such as alcohols, ethers, alkyl halides, etc.

When employing methyl compounds as methanol, demethyl ether, and methyl halides as alkylating agents, hypothetical methylene probably forms (which may be represented by the formula =CH2) and serves as the active alkylating or methylating agent. For convenience methylene may herein be considered as the first member of the'olefln serieswhlch undergoes reaction for example with benzene to produce toluene and poly-methyl benzenes while other aromatic hydrocarbons may similarly yield other methylatedaromatic hydrocarbons. The differeither normally gaseous or normally liquid and comprise ethylene and its higher homologs both gaseous and liquid, the latter including various polymers of normally gaseous olefins. Cyclic olefins may also serve as alkylating agents but gen-,-

erally under conditions of operation different from those employed in the alkylation of aromatic hydrocarbons with non-cyclic straight and branched chain olefins. Cyclo-parafilns with three and/or four carbon atoms in the ring may also be employed as alkylating agents for aromatichydrocarbons. Olefinic hydrocarbons utilizable as alkylating agents are obtained from any source and comprise products of catalytic and thermal cracking of oils or those obtained by dehydro genatng the corresponding parafiinic hydrocarbons or by dehydrating alcohols.

The addition of an alkyl group to an aromatic hydrocarbon may thus be effected in the presence of a ferrous chloride-containing catalyst using as alkylating agent an olefin or a substance capable of producing an olefin under the operating conditions.- Such olefin-producing substances include alcohol and ethers which undergo dehybons. .Alkyl halides may be employed similarly cut alkylating agents or methylating agents, however, are not necessarily used under the same conditions of operation to form desired products.

Suitable catalysts for use in efiecting the process of the present invention comprise composites of ferrous chloride and a carrier such as alumina, silica-alumina composites, clays, diatomaceous earth, charcoal, etc. The different carriers which may be employed are not-necessarily equivalent in their action.

The proportions of carrier and ferrous chloride may be varied as desired to make catalyst composites of different activities. Thus it has been found possible and practical to make stable granular catalysts resistant to disintegrating influences by using from about 5 to about 50% by weight of ferrous chloride and from about 95 to about 50% by weight of activated alumina or an alumina-containing carrier. These materials 'in finely powdered form, after thorough mechanical mixing, may be subjected to drying, pelleting, and heating operations to produce formed parv ticles of catalyst suitable for use a alkylation reactor filling material. A suitable carrier may also be impregnated with an aqueous solution of ferrous chloride, dried and heated or calcined in a reducing atmosphere-to form a ferrous chloridecarrier composite suitable for use in promoting the alkylation of an aromatic hydrocarbon.

Alkylations of the type hereinabove set forth may also-be effected in the presence of hydrogen and/or of hydrogen" chloride. There is little or no carbon formation upon the catalyst when al-' kylations are carried out under hydrogen pressure but carbon formation does occur to a substantial extent in the absence of hydrogen. Hydrogen chloride introduced to the reaction mixture appears to exert a promoting effect upon the ferrous chloride-containing catalyst, particularly when the alkylating agent employed does not containa substantial proportion of combined halogen.

. 3 carbons and an alkylating agent as an olefl'nic hydrocarbon according to the process or the present invention, the exact method J ofprocedure varies with the nature of the reacting constituents- A simple procedure, utilizablein the case of an aromatic hydrocarbon which is normally liquid or if solid is readily soluble or easily dispersible in a substantialy inert-liquid anda normally gaseous or liquid olefinic hydrocarbon, consists in contacting the aromatic and oleflnic'hydrocarbons with a. composite of --ferrous chloride and a carrier at a temperature of from about 100 toabout 500. C. but preferably between about 250 and about350" C. under a pressure of from substantially atmospheric to approximately 300 atmospheres. Intimate contact of the reacting components with the catalyst is eflected by passing the reaction mixture through a fixed bed of the granular catalyst containing ferrous chloride or the reacting components may be mixed with finely divided catalyst in a substantially fluid type of operation. In the hydrocarbon mixture subjected to alkylation treatment it is preferable to have present between about 1 and about moaromatic hydrocarbon is charged to such a re-- actor while the fraction containing olefinic hydrocarbons as such or preferably diluted by another portion of the aromatic hydrocarbon being treated, is introduced at various points between 4 forms substantially no addition compounds or complexes with aromatic and/or oleflnic hydrocarbons.

The reactions between olefinic and aromatic hydrocarbons in the presence of supported ferrous chloride are basically of a relatively-simple character although they may be accompanied by certain amounts of destructive hydrogenation when the alkylation reaction is carried out under a relativelyhigh hydrogen pressure at' a temperature above about 350 C. Apparently a typical alkylation reaction involvesthe addition of the aromatic hydrocarbon to the double bond of an olefinic hydrocarbon to produce an alkylated aromatic hydrocarbon which may in turn undergo further reaction with one or more molecular pro- 1 portions of the oleflnic hydrocarbon thus producing di-alkylated aromatic and poly-alkylated aromatic hydrocarbons. Within certain limits it is possible to. produce mainly mono-alkylated aromatic hydrocarbons by proper adjustment of catalyst activity, ratio of oleflnic' to aromatic hydrocarbons, operating conditions of temperature, pressure, rate of feed, etc.

The reaction between an aromatic hydrocarbon and a hexene or other normally liquid olefin of higher molecular weight may also involve a depolymerization or splitting or, the olefin into olefin fragments of lower molecular weight which react with the aromatic hydrocarbon to produce allqlated aromatic hydrocarbons. Thus benzene and di-isobutene or trl-isobutene react and yield tertiary butyl benzene and poly-tertiary butyl the inlet and outlet of the reaction zone in such a way that the reaction mixture being subjected to contact with the granular ferrous chloridecontaining catalyst will at all times contain a relatively low proportion of the oleflnic hydrocarbon and thus favor alkylatlon rather than polymerization.

While the methods of passing the aromatic and oleflnic hydrocarbons, either together or countencurrently. through a suitable reactor containing the granular catalyst are generally customary procedures, the condensation or alkylation reaction between aromatic and oleflnic hydrocarbons may also-be effected in a closed vessel in which some or the reacting constituents are in fluid phase and in which the. catalyst is preferably in finely divided form and maintained in dispersion or suspension by some method of agitation. Reacting. constituents may also .be contacted in mixed phase to efl'ect a similar type oi! reaction.

The choiceofoperating procedure is dependent is a preferred catalyst as it permits continuous alkylation with a, fixed catalyst, bed and thus avoids mechanical problems as well as oxidation 7 and corrosion dimculties encountered in alkylation carriedout in'the presence "or sulfuric acid. A' ferrous chloride-carrier composite also has ,the advantage over supported aluminum chloride in that i'errous' chloride contained in-the compo ites benzenes while nonene and benzene may yield both butyl and amyl benzenes by so-called depolyalkylatlon.

In general, the'products formed by interaction of an olesflnic hydrocarbon with a molal excess of an aromatic hydrocarbon are separated from the unreacted aromatic hydrocarbon by suitable means as by distillation, and the unreacted portion of the aromatic hydrocarbon originally charged and generally the poly-alkylated hydrocarbons formed are returned to the process and mixed with additional quantities of the oleflnic and aromatic hydrocarbons being charged to contact with the ferrous chloride-containing catalyst. This recycling of poly-alkylated aromatic hydrocarbons aids in the production of mainly mono-alkylated aromatic hydrocarbon and depresses the formation of more-highly alkylated derivatives. The'total alkylated product thus freed from the excess of the originally charged aromatic hydrocarbon is separated into desired tion of the ferrous chloride or to otherconversions which are'not clearly. understood.

The'following examples are given to illustrate the character of results obtained by the use of the present process although the data presented are only from a selected case and are not intro-'- duced with the intention of unduly restricting the generally broad scope or thelnvention. "sam l r v To 300 parts by weight of 5 x 5 mm. alumina pellets was added a solution'prepared by dissolving "156 parts by weight of ferrous chloride '5 tetrahydrate in 100 parts'by weight of warm water. Only two-thirds of the solution was absorbed by the alumina pellets in the first impregnation. As a test portion of the pellets coated by ferrous chloride and dried in an oven at 100 C. showed no signs of oxidation, the remainder was dried also at 100 C. before completing the impregnation. However, some oxidation occurred and many of the pellets became reddish brown in color. The reddish brown pellets were found to contain ferric oxide as an oxi- I dation product. The dried pellets were impregnated with the remainder of the ferrous chloride solution and were then heated in hydrogen at 300 C. for 12 hours.

80 parts by weight of benzene, 21 parts by weight of propene, and 15' parts by weight of the above indicated ferrous chloride-alumina catalyst containing approximately 25% by weight of ferrous chloride were placed in an autoclave to which hydrogen was added to an initial pressure.

of 100 atmospheres and then the reaction mixture was heated at 350 C. for 4 hoursunder a maximum pressure of 240 atmospheres. The resulting reaction product yielded 39- parts by weight of iso -propyl benzene, 7.3 parts by weight matic hydrocarbon and a normally gaseous olefin to contact at a temperature of from about 100 to about 500 C. under a pressure of from substantially atmospheric to approximately 300 atmospheres in the presence of hydrogen and of a catalyst comprising essentially a composite of ferrous chloride and a carrier.

7. A process for producing alkylated aromatic hydrocarbons which comprises subjecting an arcmatic hydrocarbon and a normally liquid olefin to contact at a temperature of from about 100 to about 500 C. under a pressure of from subof di-isop'ropyl benzene, and 2.7 parts by weight of more-highly propylated hydrocarbons. Upon the basis of the propane charged, the yields of isopropyl benzene and di-isopropyl benzene were Y65 and 18%, respectively.

Example I! 80 parts by weight of benzene, 20 parts by weight of methanol, 2 parts by'weight of hydrogen chlorlde;=and 15 parts byweight of the catalyst described and used in Example I were placed .in an autoclave to which hydrogen was added to 100 atmospheres initial pressure. The resulting reaction mixture after heating for 4 hours at- 350 C. under a maximum pressure of 247 atmospheres yielded 3.1 parts by weight of methylated benzenes, chiefly poly-methyl benzenes;

' The nature of the present invention and its commercial utility can be seen from the specification and examples given, although neither section is intended to limit its generally broad scope.

We claim as our invention:

1. A process for producing alkylated aromatic hydrocarbons which comprises subjecting an aromatic hydrocarbon and an olefin'to contact under alkylatingconditions in the presenceof a catalyst containing ferrous chloride'as its active ingredient.

2. A process for producing alkylated aromatic hydrocarbons which comprises subjecting an arcmatic hydrocarbon and an olefin to contact under alkylating conditions in the presence of a catalyst comprising essentially a composlte of ferrous chloride and a carrier.

3. A process for produc ng alkylated aromatic hydrocarbons which comprises subjecting an arcmatic hydrocarbon and an olefin to contact at a temperature of from about l00'to about 500 C. in the presence of a catalyst comprising essen- Sally a composite of ferrous chloride and a car- 4. A process for producing alkylated aromatic hydrocarbons which comprises subjectingan arcmatic hydrocarbon and an olefin to contact at a temperature of from about 100 to about 500 C. under a pressure of from substantially atmospheric to approximately 300 atmospheres in the presence of a.cata1yst comprising essentially a composite of ferrous chloride and a carrier.

stantially atmospheric to approximately 300 atmospheres in the presence of hydrogen and of a catalyst comprising essentially a composite of ferrous chloride and a carrier.

8. A process for producing alkylated aromatic hydrocarbons which comprises subjecting an arcmatichydrocarbon and an olefin to contact at a temperature of from about 100 to about 500 C. under a pressure of from substantially atmospheric to approximately 300 atmospheres in the presence of a hydrogen halide and of a catalyst comprising essentially a composite of ferrous chloride and'a carrier. i

9; A process for producing alkylated aromatic I hydrocarbons which comprises subjecting an arcmatic hydrocarbon and an olefin to contact at a.

temperature of from about 100 to about 500 C. under a pressure of from substantially atmospheric to approximately 300 atmospheres in the presence of hydrogen, a hydrogen-halide, and a catalyst comprising essentially a composite of ferrous chloride and a carrier. I

10. A process for producing alkylated aromatic hydrocarbons which comprises subjecting'an aromatic hydrocarbon and an olefin to contact at a temperature of from about 100 to about 500 C. under a pressure of from substantially'atmospheric to approximately 300 atmospheres in the presence of hydrogen and of a catalyst comprising essentially a composite of ferrous chloride and an alumina-containing carrier.

11. A process for producing alkylated aromatic hydrocarbons which comprises subjecting an arcmatic hydrocarbon and an olefin to contact at a temperature of from about 100. to about 500 C; under a pressure of from substantially atmospheric to approximately 300 atmospheres in the presence of hydrogen and of a catalyst comprising essentially a composite of ferrous chloride,

. mospheres in the presence of hydrogen and of a catalyst comprising essentially a composite of ferrous chloride and alumina. 

